1. Field of the Invention
The invention relates to a product authentication or identification system and, more particularly, to a system for marking a product with a special code and later verifying the authenticity of that product by reading the special code.
2. Description of the Related Art
Various techniques have been used to identify products in an effort to reduce counterfeiting. For collectibles such as art works and sports memorabilia, where a single item may be worth millions of dollars, a technique that is highly refined and virtually impossible to copy is desired. This is because high potential counterfeiting gains will motivate counterfeiters to invest large sums of money and resources to defeat the anti-counterfeit measure. Similarly, the high cost of implementing an anticounterfeit measure for collectibles is typically accepted by the owner or insurer, because the potential loss from counterfeiting is great.
On the other hand, for mass produced items such as apparel, CDs, and audio and video cassettes, cost is a more important factor in implementing an anti-counterfeit measure. The implementation cost must be small enough so that the cost of the protected product will not increase dramatically. Yet, the anti-counterfeit measure must be refined enough so that counterfeiters will be unable to defeat the anti-counterfeit measure in a sufficiently easy manner such that they will be able to economically produce and sell counterfeit goods.
Mass produced items also have to be protected against product diversion. Product diversion occurs when a counterfeiter acquires genuine, non-counterfeit goods that are targeted for one market and sells them in a different market. The counterfeiter does this to circumvent the manufacturer""s goal of controlling the supply of his or her goods in a particular market and, as a consequence, benefits from the sales in that limited supply market or in the diverted sales market.
In one type of anti-counterfeit and anti-diversion measure, an ultraviolet (UV) ink is used to mark the product with an identifying indicia. One benefit of using the UV ink is that it is typically not visible when illuminated with light in the visible spectrum (380-770 nm), but is visible when illuminated with light in the UV spectrum (200-380 nm). Therefore, counterfeiters will be unable to tell whether the product contains a security mark by merely looking at the product when the product is illuminated with visible light.
A number of UV inks are readily available in the security industry and can be obtained at a relatively low cost. Several UV ink types and compositions are described, for example, in U.S. Pat. No. 5,569,317, entitled xe2x80x9cFluorescent and Phosphorescent Tagged Ink for Indiciaxe2x80x9d the disclosure of which is incorporated by reference herein. This patent discloses a security mark that becomes visible when illuminated with UV light having a wavelength of 254 nm.
However, the use of security marks containing a UV ink has seen increased use and counterfeiters have become knowledgeable about their use. It has been a common practice for counterfeiters to examine the UV ink from a product sample, reproduce or procure the same or similar UV ink that matches the characteristics of the UV ink from the product sample, and apply the same security mark on the counterfeit products using the substitute UV ink.
In another type of anti-counterfeit and anti-diversion measure, an infrared (IR) ink is used to mark the product with an identifying indicia. As with the UV ink, one benefit of using the IR ink is that it is typically not visible when illuminated with light in the visible spectrum, but is visible when illuminated with light in the IR spectrum (800-1600 nm). An additional benefit of using the IR ink is that it is more difficult to reproduce or procure the matching IR ink by studying a product sample containing the IR security mark. Examples of IR security mark usage are given in U.S. Pat. No. 5,611,958 and U.S. Pat. No. 5,766,324. The disclosures of these patents are incorporated by reference herein.
Combination security marks have also been proposed. In U.S. Pat. No. 5,360,628 and U.S. Pat. No. 5,599,578, the disclosures of both of which are incorporated by reference herein, a security mark comprising a visible component and an invisible component made up of a combination of a UV dye and a biologic marker, or a combination of an IR dye and a biologic marker is proposed. Also, in U.S. Pat. No. 5,698,397, the disclosure of which is incorporated by reference herein, a security mark containing two different types of up-converting phosphors is proposed.
The detection of invisible security marks is performed automatically using a photodiode, for example, or manually by observing the fluorescence that results from illumination with a UV or IR light source. Sometimes, an invisible security mark is printed as an invisible bar code, as in U.S. Pat. No. 5,502,304, U.S. Pat. No. 5,525,798, U.S. Pat. No. 5,542,971, and U.S. Pat. No. 5,766,324, and is read using a bar code reader.
In the conventional product identification systems described above, the security mark emits light in a predetermined range of wavelengths in response to an excitation light. These systems are secure, because a counterfeiter does not generally know that a security mark exists, where it is applied, or how to excite it. However, once the counterfeiter gains access to this information, security is compromised, because the counterfeiter would be able to duplicate the security mark by using a phosphor that emits light in the same range of wavelengths.
An object of this invention is to provide a product authentication or identification system that offers a greater level of security that than the conventional systems.
This and other objects of the invention are achieved with a product authentication or identification system that uses a mark containing mixtures of optical components so that when the mark is excited, it fluoresces and emits light across the spectrum. In this system, even if the counterfeiter learned how to reproduce the excitation light and where to aim the excitation light, the counterfeiter would not be able to duplicate the security mark, because he or she would not know which part of the spectrum carried the authentication signal.
Another advantage of the invention is that the marking and detecting processes described below are non-destructive and dry.
Additional objects, features and advantages of the invention will be set forth in the description of preferred embodiments which follows.